1、Designation: D 3790 79 (Reapproved 2006)Standard Test Method forVolatile Matter (Moisture) of Leather by Oven Drying1This standard is issued under the fixed designation D 3790; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the de
3、termination of volatilematter (moisture) in all types of leather.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the appl
4、ica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2813 Practice for Sampling Leather for Physical andChemical TestsE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals3. Summary of Tes
5、t Method3.1 The ground leather specimen is heated in a mechanical-convection oven for 16 h at 100C, placed in a desiccator,cooled, and reweighed. The loss in weight represents thevolatile matter.4. Significance and Use4.1 The result obtained by this test is normally considered tobe the moisture cont
6、ent of the leather sample. This result isused to correct all other chemical tests to a moisture-free basis.4.2 Materials that are volatile under these conditions, otherthan water, may be present in the leather, although their amountin any normal leather would be expected to be a very smallpercentage
7、 of the total volatile matter.4.3 Under the conditions of this test, certain materials inleather, such as protein fiber and chromium tanning salts, mayretain moisture. Other materials, such as tannins and oils, maybe oxidized. Both of these effects produce negative errors inthe moisture determinatio
8、n.4.4 The amount of volatile matter (moisture) released by agiven leather varies with (a) degree of grinding of the sample,(b) weight of sample taken, (c) temperature and time of theoven drying, (d) shape of the weighing container, and (e) typeof oven (gravity versus mechanical convection) used.4.5
9、Because of the above unknown errors, the result of thistest is a purely arbitrary value for the moisture content of thesample. It is, therefore, essential that the method be followedexactly in order to obtain reproducible results among labora-tories. This is particularly true if other chemical analy
10、tical testsbeing performed on the same sample are reported on themoisture-free basis.5. Apparatus5.1 Weighing Bottle3, glass, low-form, cylindrical with aground-glass stopper of standard taper. The bottle shall have 706 5 mm inside diameter, and 33 6 3 mm overall height.5.2 Oven, mechanical-convecti
11、on draft capable of setting at100C, with a thermoregulator system capable of holding oventemperature within 6 2C of set point.Athermometer accurateto 60.2C should be used to check and monitor the oven setpoint.5.3 Balance, capable of weighing up to 100 g with anaccuracy of 60.001 g.5.4 Desiccator, a
12、ny convenient form or size, using anynormal desiccating agent such as calcium sulfate, calciumchloride, or silica gel.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.06 on Chemical Analysis.Current edition approved Oct.
13、 1, 2006. Published November 2006. Originallyapproved in 1979. Last previous edition approved in 2001 as D 3790 - 79(2001)2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, ref
14、er to the standards Document Summary page onthe ASTM website.3Weighing bottles that have been found to be satisfactory are the Kimble GlassCo. No. 15166 and 15165 with 71/15 standard-taper caps and are available frommost laboratory supply houses.1Copyright ASTM International, 100 Barr Harbor Drive,
15、PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Sampling6.1 The leather shall be sampled in accordance with PracticeD 2813.7. Procedure7.1 Insert the empty weighing bottle inside the invertedstoppered cap and place on a shelf in the oven at 100 6 2C for1 h or more. If the stopper has
16、 a handle then the stopper maybe placed on the shelf in the oven near the empty weighingbottle.7.2 Remove and place in a desiccator for at least 2 h to cool.7.3 Weigh and record to the nearest 60.001 g.7.4 Use the ground leather sample as specified in PracticeD 2813 and transfer 5 6 1 g of ground le
17、ather into thepreviously weighed weighing bottle and stopper the bottle.7.5 Weigh the stoppered bottle to the nearest 60.001 g andrecord.NOTE 1Since leather varies greatly in moisture content dependingupon the humidity of the surrounding atmosphere, it is essential thatweighings be made rapidly from
18、 the sample. It is further recommendedthat no weighings of samples be carried out if the humidity of theatmosphere at the balance varies by more than 620 % from the humidityconditions under which the sample was equilibrated.NOTE 2The specimens for all chemical tests to be reported on amoisture-free
19、basis should be weighed out at the same time as the moisturespecimens.7.6 Oven DryingInsert the weighing bottle containing thesample inside the inverted stoppered cap and place on a shelfin the mechanical-convection oven at 100 6 2C for 16 612h.7.7 Recap the bottle, place in the desiccator, and cool
20、 for atleast 2 h.7.8 Weigh and record to the nearest 60.001 g.8. Calculations8.1 Calculate the percent volatile matter (moisture) as fol-lows:Volatile matter moisture!,%5S 2 DS 2 B3 100 (1)where:S = weight, of original specimen plus bottle plus cap, g,B = weight, of empty bottle plus cap, g, andD =
21、weight, grams, of oven-dried sample plus bottle pluscap, g.9. Report9.1 Report the percent volatile matter on the as-receivedbasis for each of the two specimens and the average of the twospecimens to the nearest 0.01 %.10. Precision and Bias410.1 RepeatabilityThe average difference between tworesult
22、s obtained by the same analyst on different days willapproximate 0.2 % absolute. Two such values should beconsidered suspect (95 % confidence level) if they differ bymore than 0.5 % absolute.10.2 ReproducibilityThe average difference between tworesults (each the average of duplicate determinations)
23、obtainedby analysts in different laboratories will approximate 0.3 %absolute. Two such values should be considered suspect (95 %confidence level) if they differ by more than 0.9 % absolute.10.3 This method is purely arbitrary and the bias cannot berelated to the true moisture content of the sample.1
24、1. Keywords11.1 moisture; volatile matterASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and th
25、e riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision o
26、f this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should
27、make your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtaine
28、d by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).4The precision estimates are based on an interlaboratory study of six differenttypes of leather. One analyst in each of five laboratories performed two analyses oneach sample on successive days for a total of 60 analyses. Practice E 180 was usedin developing these precision estimates.D 3790 79 (2006)2
